where \(m\)  is the actual number of edges [1]}. Notice that if the network is fully connected, the actual number of edges is \(n(n-1)\) . Therefore, the density is a measure of the network sparsity. Given the density \(\rho \) , the average (in) degree of the network, denoted by \(\left\langle k \right\rangle \) , is
\(\left\langle k \right\rangle = \frac{m}{n} = \left( {n - 1} \right)\rho \approx n\rho .\) 
